MongoDb get all match data from deeply nested array document - mongodb

Question

How to get education data (include the parent) for each family member in families that has year 2006? Supose I have data in mongodb:
{
"name": "Families",
"size": 3,
"families": [
{
"name": "Johny's Family",
"size": 2,
"family_member": [
{
"name": "Ruben",
"age": 22,
"education": [
{
"school": "Edward Academy",
"year": 2003
}
]
},
{
"name": "Hana",
"age": 20,
"education": [
{
"school": "Edward Academy",
"year": 2006
},
{
"school": "Nanyang University",
"year": 2012
}
]
}
]
},
{
"name": "Boy's Family",
"size": 1,
"family_member": [
{
"name": "Boy",
"age": 23,
"education": [
{
"school": "Broklyn Academy",
"year": 2003
},
{
"school": "Home School",
"year": 2006
}
]
}
]
}
]
}
I have try to get it using plain find function in mongodb but the result is not realy I wanted. this is my mongo script:
db.getCollection('tester').find(
{
"name":"Families",
"families.family_member.education.year":2006
},
{
"families.$.family_member.education.year":1
}
)
Can anyone suggest the best method to get the data become something like this:
{
"name": "Families",
"size": 3,
"families": [
{
"name": "Johny's Family",
"size": 2,
"family_member": [
{
"name": "Hana",
"age": 20,
"education": [
{
"school": "Edward Academy",
"year": 2006
}
]
}
]
},
{
"name": "Boy's Family",
"size": 1,
"family_member": [
{
"name": "Boy",
"age": 23,
"education": [
{
"school": "Home School",
"year": 2006
}
]
}
]
}
]
}

Answer 1

You may use JavaScript code to process your data because mongodb return data in unit of Document.
process "families" field like this:
doc.families.map((family)=>{
family.family_member = family.family_member.map((member)=>{
member.education = member.education.filter((edu)=>edu.year==2006);
return member;
});
return family;
})

Answer 2

You can try this one. You can get expected result using aggregation and you have to use $unwind then $match and $group
db.CollectionName.aggregate([
{$unwind: "$families"},
{$unwind: "$families.family_member"},
{$unwind: "$families.family_member.education"},
{$match: {"families.family_member.education.year": 2006}},
{
$group: {
_id: "$_id",
name: {$first: "$name"},
size: {$first: "$size"},
families: {$push: "$families"}
}
}
])

Answer 3

Using aggregation pipeline we can get this result. To achieve this use $unwind and $match. $unwind need to be used twice since we have deeply nested arrays
db.tester.aggregate([
{$unwind:"$families"},
{$unwind:"$families.family_member"},
{$unwind:"$families.family_member.education"},
{$match:{"families.family_member.education.year":2006}}
])

Answer 4

Change your query like below, It should work:-
db.getCollection('tester').find({"families.family_member.education.year": 2006},{"families.family_member.education.year":1})
OR
If you want to print whole things, use only this:-
db.getCollection('tester').find({"families.family_member.education.year": 2006}
Thanks.